1. Field of the Invention
The present invention relates to an electronic musical instrument and, more particularly, to an electronic musical instrument, which shifts and outputs the tone pitches of externally input voice signals in real time.
2. Description of the Prior Art
Electronic toys, which shift and output the tone pitches of voice signals externally input through a microphone, are known.
FIG. 5 is a block diagram showing a general arrangement of an electric musical instrument having a conventional tone pitch conversion function. As can be seen from the block diagram of FIG. 5, the electronic musical instrument converts an externally input voice into a voice signal S.sub.20 through a microphone 20, and supplies the converted signal to a pitch converter 21.
The pitch converter 21 receives a signal S.sub.21 for controlling the tone pitch of the voice signal S.sub.20 from a pitch shift control circuit 22. The pitch shift control circuit 22 is provided with an operation switch, which can be operated by a user to control the tone pitch of the input voice. The operation switch comprises, e.g., a push-button switch. Every time the user operates the operation switch, the content of the pitch control signal S.sub.21 to be supplied to the pitch converter 21 is shifted by one step. For example, every time the operation switch is operated, the shift width of the tone pitch of the voice signal S.sub.20 is increased or decreased by a semitone interval.
The pitch converter 21 shifts the tone pitch of the voice signal S.sub.20 according to the content of the input pitch control signal S.sub.21 to generate a pitch-converted voice signal S.sub.22, and supplies the signal S.sub.22 to an amplifier 23. The pitch-converted voice signal S.sub.22 supplied to the amplifier 23 is amplified to a predetermined level, and the amplified signal is externally produced as a tone through a loudspeaker 24.
The conventional electronic musical instrument shifts the tone pitch of the voice signal S.sub.20 every time the user operates the switch of the pitch shift control circuit 22. For this reason, the shift width of the tone pitch, which can be shifted by a single operation, is limited.
More specifically, as described above, the tone pitch of the voice signal S.sub.20 is shifted by a semitone interval every time the operation switch is depressed once. Thus, a pitch shift operation for instantaneously shifting the tone pitch by, e.g., three tone intervals cannot be performed. For this reason, the conventional function is used for simply shifting the tone pitch, and it is difficult to use this function together with several other of musical factors.